FIG. 4 is a side view showing an overall configuration of a hybrid shovel serving as an example of a hybrid construction machine. FIG. 5 is a plan view showing an example of a layout of devices on an upper frame, the layout being envisaged in the hybrid construction machine shown in FIG. 4.
As shown in FIG. 4, the shovel includes a crawler type lower propelling body 1, an upper slewing body 2 provided on the lower propelling body 1 to be capable of slewing about a perpendicular axis to a ground surface, and a working attachment 6 provided on a front portion of the upper slewing body 2. The working attachment 6 includes a boom 3, an arm 4, and a bucket 5.
As shown in FIG. 5, the upper slewing body 2 includes an upper frame 7 serving as a base, a cabin 8 provided on a front portion left side of the upper frame 7, and a counterweight 9 provided in a rear end portion of the upper frame 7.
Note that in this specification, “front-rear” and “left-right” indicate directions seen from an operator sitting in the cabin 8.
The upper slewing body 2 also includes a partition plate 10 extending in the left-right direction behind the cabin 8, an engine 12 serving as a power source and disposed in an engine room 11 formed between the partition plate 10 and the counterweight 9, and a hydraulic pump 14 driven by power from the engine 12. The engine 12 is disposed in a lateral attitude such that an output shaft thereof extends in the left-right direction.
The upper slewing body 2 of the hybrid shovel further includes a generator motor 13 provided on the upper frame 7 on one side (a right side in the drawing; the following description, including the embodiment, is based on this example) of the engine 12 in the left-right direction. The generator motor 13 is capable of operating as both a generator and a motor. More specifically, the generator motor 13 is driven as a generator by the power of the engine 12. Further, the generator motor 13 is arranged with respect to the hydraulic pump 14 in the left-right direction.
Note that an engine cooling radiator, a cooling fan, and so on are provided on a left side of the engine 12. These components are not directly related to the present invention, and have therefore been omitted from the drawings.
The upper slewing body 2 further includes left and right vertical plates 15, 16 that stand on the upper frame 7 in a left-right direction intermediate portion of the upper frame 7 with a left-right direction interval, and extend over substantially an entire front-rear direction length of the upper frame 7. The boom 3 shown in FIG. 4 is attached to front portions of the both vertical plates 15, 16.
Further, as shown in the drawing, the generator motor 13 is disposed on an inner side of the right vertical plate 16 (between the right vertical plate 16 and the left vertical plate 15).
Furthermore, the upper slewing body 2 includes a fuel tank 17, an operating oil tank 18, an electric storage device 19, and a control device 20. The fuel tank 17 and the operating oil tank 18 are arranged on the upper frame 7 in the front-rear direction on an outer side of the right vertical plate 16 (an outer side in a width direction of the upper slewing body 2, i.e. on the right side of the right vertical plate 16). The electric storage device 19 is provided in front of the tanks 17, 18, in other words on a front portion right side of the upper frame 7, and serves as a power source for operating the generator motor 13 as a motor. The control device 20 controls operations of the electric storage device 19 and the generator motor 13.
In other words, the generator motor 13, the electric storage device 19, and the control device 20 constitute hybrid devices. Of these hybrid devices, the generator motor 13 is disposed in a rear portion of the upper frame 7 while the electric storage device 19 and the control device 20 are disposed in the front portion of the upper frame 7.
When there is no particular need to differentiate between the electric storage device 19 and the control device 20 in the following description of the present invention, including the embodiment, these two components will occasionally be referred to collectively as a “front portion hybrid device”. A reference numeral “21” in FIGS. 1, 2, 5, and 6 denotes the front portion hybrid device collectively.
Note that the layout described above, in which the electric storage device 19 and the control device 20 are disposed on the front portion right side of the upper frame 7, is an example of a layout envisaged for use in a hybrid shovel. Another example of a layout of a electric storage device and a control device is disclosed in Patent Document 1.
FIG. 6 is a schematic plan view showing an example of wiring in an electric power system and a signal system for connecting the devices on the upper frame, the example being envisaged in the hybrid construction machine shown in FIGS. 4 and 5. Note that the partition plate 10 and the engine room 11 shown in FIG. 5 have been omitted from FIG. 6.
A reference symbol S1 in FIG. 6 denotes an intermediate space sandwiched between the left and right vertical plates 15, 16. Further, a reference symbol S2 denotes a right outside space on an outer side (the right side) of the right vertical plate 16. A reference symbol S3 denotes a left outside space on an outer side (the left side) of the left vertical plate 15.
As shown in FIG. 6, the upper slewing body 2 includes an electric power cable 22 and a signal cable 23 for electrically connecting the generator motor 13 to the front portion hybrid device 21. The electric power cable 22 transmits electric power between the generator motor 13 and the front portion hybrid device 21 (the electric storage device 19). The signal cable 23 transmits signals such as a control signal and a sensor signal between the generator motor 13 and the front portion hybrid device 21 (the control device 20).
Electromagnetic wave noise is generated in the electric power cable 22 by a high voltage large current flowing through the electric power cable 22, and this electromagnetic wave noise adversely affects the signal cable 23, through which a weak current flows. As a result, signal transmission may be obstructed.
As shown in FIG. 6, therefore, it is thought that the two cables 22, 23 are laid along separate routes in order to suppress the effect of the electromagnetic wave noise on the signal cable 23.
More specifically, the electric power cable 22 is laid along a route as follows. The route starts from the intermediate space S1 in which the generator motor 13 is disposed, passes through the right vertical plate 16 into the right outside space S2, and then passes through the right outside space S2 along the right vertical plate 16 until reaching the front portion hybrid device 21.
The signal cable 23, meanwhile, is laid along a bypass route as follows. The bypass route starts from the intermediate space S1, passes through the left vertical plate 15 into the left outside space S3, extends along the left vertical plate 15 until reaching a front portion of the left outside space S3, passes through the left vertical plate 15 into the intermediate space S1, passes through the right vertical plate 16 into the right outside space S2, and then reaches the front portion hybrid device 21.
In other words, the two cables 22, 23 are laid along routes set such that the two cables 22, 23 are as far removed from each other as possible by the two vertical plates 15, 16, which are constituted by conductors (steel plates) capable of blocking electromagnetic wave noise.
According to the wiring structure described above, however, the signal cable 23 is laid along a long-distance bypass route that passes through the three spaces S1 to S3. More specifically, the signal cable 23 is laid along a long-distance bypass route passing through the left outside space S3, the intermediate space S1, and then the right outside space S2 from the intermediate space S1. The electric power cable 22 is also disposed along a comparatively long route extending from the intermediate space Si to the right outside space S2. The respective cables 22, 23 must therefore be laid so as to avoid the devices disposed compactly on these long routes. As a result, a wiring operation becomes extremely complicated. Further, there also be a defect in which a required cost of the wiring becomes increase by increasing a required cable length.
Patent Document 1: Japanese Unexamined Patent Application No. 2004-169465